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Biocatalyst production in the cells of Lactobacillus brevis

Cultivation of Lactobacillus brevis cells was carried out in this work. The aim was to produce intracellular enzymes: NADH oxidase (NOX) and alcohol dehydrogenase (ADH). The cells were cultivated in the batch bioreactor (V = 1 dm3) using the MRS medium at the temperature of 30 °C and pH 6.3. Since the production of the target enzymes depends on the oxygen concentrations [1], experiments were performed with the different ways of oxygen supply in the bioreactor. Concentration of biomass, glucose and lactic acid, as well the activity of NOX and ADH were monitored during the experiments. Mathematical model of the process was proposed. Biomass and glucose were described by the unstructured Monod model. Luedeking-Piret model for the partially grow associated product formation was used to describe the production of lactic acid and examined enzymes. The highest level of the NADH oxidase was produced by L. brevis during aerobic growth, while for the alcohol dehydrogenase, the highest activity was detected in the experiment without oxygen and nitrogen supply. Anaerobic conditions were found as the best for the lactic acid production

Lactobacillus brevis; alcohol dehydrogenase; NADH oxidase; modelling

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